Mechanism for regulating the charging rate of storage batteries.



. W. NOBLE. V MECHANTSM FOR REGULATING THE CHARGTNG RATE OF STORAGEBATTERIES.

APPLICATION FILED NOV. 23. 1911.

1,157,028. Patented Oct. 19, 1915.

2 SHEETS-SHEET I.

W. NOBLE.

MECHANISM FOR REGULATING THE CHARGING RATE OF STORAGE BATTERIES.

APPLICATION FIL'ED NOV- 23. 191]. 1,157,028. Patented Oct. 19, 19.15.

2 SHEETS-SHEET 2- UNITED STATES PATENT OFFICE.

WARREN NOBLE, 0F ORCHARD LAKE, MICHIGAN, ASSIGNOR TO SANGAMO ELECTRICCOMPANY, OF SPRINGFIELD, ILLINOIS, A CORPORATION OF ILLINOIS.

MECHANISM FOR REGULATING THE CHARGING RATE OF STORAGE BATTERIESSpecification of Letters Patent.

Patented Oct. 19, 1915.

Application filed November 23, 1911. Serial No. 662,046.

To all ,whom it may concern Be it known that I, IVARREN NOBLE, a subjectof the King of Great Britain, residing at Orchard Lake, in the county ofOakland and State of Michigan, have invented certain new and usefulImprovements in Mechanisms for Regulating the Charging Rate of StorageBatteries, of which the following is a specification, reference beinghad to the accompanying drawings.

My invention relates to mechanism for properly charging storagebatteries, and especially to mechanism by which the charging rate may bevaried as the charge progresses, in accordance with the character andnature of the battery which is being charged.

In some types of storage batteries the nature of the battery is suchthat the charging rate requires to be diminished as the chargingprogresses. In other types it is desirable to have the charging rateincreased as the charge progresses. In batteries of the so-called leadtype, in which properly prepared lead plates are immersed in a solutionof sulfuric acid, it is necessary to gradually reduce the rate of flowof the charging current as the charge progresses in order to preventundue heating and consequent disintegration of the plates. For instance,if the normal initial charging rate for a given battery is thirtyamperes, the rise in the electromotive force of the battery as thecharge progresses is not sufficient to cut the flow of the chargingcurrent down to a safe point after the battery has become partiallycharged. In consequence, if the normal initial charging rate of thecurrent is continued, the temperature of the electrolyte rises to a veryhigh point. It is necessary, therefore, gradually to reduce the flow ofthe charging current as the charging of the battery progresses. While,theoretically,-the charging rate should be reduced a number of timesduring the process of charging such a lead battery, in practice three orfour steps of reduction are suflicient to give goods results. This isusually called tapering the charge. On the other hand, in certain formsof storage batteries, and particularly in that form which has nickel andiron elements, it is found that the internal resistance of the cellsmaterially increases as the charge progresses,'so that it is desirableto increase the charging rate rather than decrease it so that thebattery maybe charged at a continuous high rate. It will be obvious thatif the internal resistance increases and if the voltage of the currentby which the battery is sought to be charged remains the same duringsuch rising internal resistance, the effective charging rate of thecurrent to the battery is cut down; that is to say, the voltageremaining the same, the rate at which the battery is effectively chargeddiminishes with the increasing internal resistance, and it thereforefollows that with some batteries of this type they cannot be completelycharged unless some effective and desirable mechanism is provided bywhich the voltage'of the charging current can be gradually increased soas to counteract the effect of rising internal resistance. It thereforebecomes desirable in such cases to gradually increase the charging rateso as to counteract the effect of rising internal resistance.

It is the object of my invention to produce a new and improvedapparatus, which, as the charging progresses, will automatically act tovary the charging rate by either cutting in or cutting out resistance inthe circuit or varying the resistance of the circuit as the battery isbeing charged, and which will also properly take into account theinitial condition of the battery with respect to charge when therecharging is begun. For instance, if the battery is recharged whenonly, say, half discharged, the same charging rate cannot effectively bemaintained for as long a time as it could be maintained if the batterywere fully discharged before the beginning of recharging.

My apparatus, therefore, has for its object to provide an apparatuswhich will not only automatically vary the charging rate, eitherincreasing it or decreasing it in accordance with the character of thebattery to be charged, but which also may be set at a desired point, inaccordance with the condition of the battery with respect to its chargewhen the recharging is begun.

In the drawings,--Figure 1 is an end elevation; Fig. 2 is a top or planview; Fig. 3 is an enlarged detail, being a portion of the actuatingscrew and the half nut driven thereby shown partially in section; Fig. 4is a diagrammatic view of the drum developed; Fig. 5 is a diagrammaticview showing portions of my mechanism and the elec tric circuitconnected therewith; and Fig. 6 is a diagrammatic view showing the formof switches to be used when it is desired to increase the charging rate.

Referring to the drawings,6 indicates a drum, which is mounted upon ashaft 7 carried in suitable bearings (not shown) so that it may berotated in said bearings as hereinafter set forth.

8 indicates a dial, which is suitably secured either to the end of thedrum or upon the shaft 7 and Whose surface is divided into a scale withdivisions adapted to read either in ampere hours or in units of specificgravity, as may be desired. The dial is so secured to the that they turntogether. As is best shown in Fig. 2 and in the development diagram inFig. 4, this drum which constitutes a controller by which the variationof the resistance in the circuit is governed, is divided into a seriesof surfaces ameter from one end of the drum to the other. Thesesurfaces, therefore, form a suitable series of steps which, preferably,

may be five in number, as is shown, but may, of course, be of lessnumber. The end of each surface is formed in a curve, as is best shownin Fig. 2 and in the development thereof in Fig. 4, so that the firststep gradually widens from one side to the other. The other steps alsogradually widen, in, however, a reverse direction, as is best shown insaid figures. These curves on which the steps are laid off are in eachcase based upon actual tests of the peculiar type of battery with whichit is to be used, and the width of any successive step in a directionlongitudinal of the drum is based upon the length of time during which acharge should continue at a given rate for the initial value ofampere-hours discharged or thespecific gravity of the battery when theis turned into such angular position as to bring the roller hereinafterdescribed along that particular longitudinal line of the drum. Thesesteps, therefore, will de-' pend upon the type of battery which it issought to charge and are readily ascertainable by actual tests of thebattery in question, and the 'drum is laid off in accordance therewith.9 indicates an arm pivoted near one end upon a suitable support, as 10,which is carried upon a carriage hereinafter described.

11 indicates a roller or cursor, which is carried upon the long arm ofthe lever 9 and is adapted to bear upon the successive surfaces of thedrum 6.

12 indicates a comprexion spring, which bears between any suitableportion of the framework, as 13, and the lever 9 so as to hold theroller or cursor 11 inconstant yielding contact with the surface of thedrum 6. The other end of the arm is preferably bent upward into a hook,as 14, for bearing upon the contact plates hereinafter described. I

15 indicatesa carriage carrying the arm 10 and adapted to turn upon andslide along a suitable rod, as 16, which is mounted in any suitableframework or casing (not shown). The carriage 15 is provided with an arm17 and a handle 18 which projects over a screw 19. The lower surface ofthe arm 17 near its end, is provided with an arc-shaped curve which isprovided with screw-threads, as is best shown in Fig. 3,

adapted to engage the threads of the screw 19, whereby, by rotation ofthe screw 19, the carriage is moved longitudinally along the rod 16carrying the arm 9 and the roller 11 longitudinally along the drum 6.The screw 19 is continuously driven. byany suitable motor, as 20,connected by suitable gears, as 21 and 22, to the screw 19 so that saidscrew is constantly driven during the charge of the battery at asuitable rateof speed.

The motor 20 may be of any approved 7 type. It may be either anelectrically-operplate will bring it in electrical contact with theplate immediately above it. The contact plates are formed of suitablespring metal and are very thin so that they may be readily moved by thelever arm, as hereinafter described. I

Referring to Fig. 5, 3536 indicate wires of an electrical circuit comingfrom any suitable generator. 37 indicates diagrammatically the storagebattery which is to be charged. 38 indicates a wire, which leads fromthe lowest contact plate 30 to the wire 35 and is connected therewith ata suitable point. 39 indicates a resistance in the wire 35 (shown, inthis case, as the positive wire). 40414243 indicates switches, which arenormally held closed by any suitable means, as springs (not shown), andwhich are interposed in the path of the circuit wire 35. H indicates aresistance coil, which is connected with each of the switches 4041--4243 by 'wires 45-464=748, whereby either the entire resistance 44 or adesired aliquot portion thereof may be interposed in the path of thecircuit 35, as is hereinafter described. 49 indicates a switch, which isinterposed between the resistance 44 and the storage battery 37.5051-52-.53 indicate coils, which, by means of wires 5455 5657, areconnected with the wire and these coils are also connected with theplates 242526 27, respectively. Each of these coils contains a core585960-61, respectively, which is magnetized when a current passesthrough the coil. These cores are placed in operative, relation,respectively, with the switches -4l4243, whereby, when the cores areenergized, the respective switches are successively opened, ashereinafter described. 62 indicates a coil having a core 63 in operativerelation with the switch 49 and connected with the circuit 36 and by awire 64 with the plate 28. It will be obvious from the abovedescription, that as long as the plate 28 is not in contact with theplate next below it, 24, the current from the generator will flowthrough the resistance 39 and the resistance 44 and the circuit composedof the wires 35 and the switches 404142-43, wire 48, switch 49, to thebattery 37, and that the current, dividing itself according towell-known principles,'

will be divided between the resistance 44 and the metallic circuitformed by the wires and the switches above named, and as the resistanceof the coil 44 is very great as compared with the resistance in theother branch of the circuit, the principal amount of the current willflow directly through the battery 37 and back by the wire 36 to thegenerator. This is the position of the parts when the roller or cursorrests upon the larger portion 6 of the drum 6. As the screw rotates, thecursor is moved longitudinally along the drum, causing the roller todrop successively to each of the surfaces 6"66 of the drum, thusbringing the contact plate 23 first into connection with contact 24 andthen connecting together successively the several contacts 23-2425-2627,operating successively the switches 4041- 4243 and gradually thusthrowing successively greater portions of the resistance 44' intothe-circuit, as will be hereinafter more fully described. When thebattery is charged, the drum is so arranged that the cursor or rollerdrops into the portion 6 thus energizing the coil 62, opening the switch49, and throwing the storage battery out of the circuit.

The above-described apparatus describes my invention when used incharging a battery in which it is desired to gradually diminish thecharging rate as the charge progresses. Fig. 6 shows another form of mydevice which is used when it is desired to increase the charging rate.In this figure the parts quite generally resemble the parts shown incorresponding portion of Fig. 5 and described above. They differ,however, mainly in that the switches are so arranged closes the contactsbetween the parts 23 to 28 the switches are closed successively, cuttingout more or less of the resistance so as to gradually increase thecurrent supplied to the battery. Referring, therefore, particularly toFig. 6, 44 44 44 and 44 indicate resistances precisely like theresistances indicated above in Fig. 5 and described by correspondingnumbers. 100-101- 102103 indicate switches which are arranged in seriesand connected by suitable wires, as 104105-106107108 with theresistances 44 44"4444. The switches 100 to 103 are normally open sothat when they are in their normal position the entire current passesthrough the resistances 44 to 44, inclusive, and thus the entireresistance is in series with the storage battery which is sought to becharged. 109110-111112 indicate magnets which by means of wires areconnected, respectively, with the bars 2425-2627 shown in Fig. 5 inexactly the same manner and by the same wire as in the devices shown inthe other figures, and also with the circuit wire 38 shown in Fig. 5 andin exactly the same manner. The effect of energizing each of thesemagnets is to close the corresponding switch so as to cut off a definiteportion of the resistance. For instance, as the bearing device travelsoff the first step of the hub the electrical circuits between bars'23and 24 are closed by the contact 30, the current energizing magnet 109closing switch 100, and thereby cutting out a portion of the resistance44, which, of course correspondingly increases the voltage of thecircuit tothe storage battery. In precisely the same manner as describedabove, and which it is believed it is not necessary to repeat here, thefarther travel of the bearing device along the hub successivelyenergizes magnets 110111112, closing successively the correspondingswitches 101-102103, gradually successively cutting out portions of theresistances 44"- 44-44 and gradually increasing the "01tage of thecurrent to the battery. It thus follows, of course, that as the coils109 to 112 are successively energized the different switches aresuccessively closed, the successive resistances cut out, and the voltageof the current through the circuit is progresas before and operates inthe same way so that when the bearing roller is upon the last step ofthe drum the coil 62 is energized, the switch 49 thrown open (see Fig.5), and the battery is entirely cut off.

Described more in detail, the operation of my device in the charging ofa battery, when it is desired to diminish the charging rate, is asfollows: If the battery is connected with an ampere hour meter, thereading of the ampere hour meter is taken and the drum is turned so thatthe roller rests upon a point thereof on the large surface 6 in a linewith the corresponding mark upon the dial. If the battery is notprovidedwith an ampere hour meter,a pilot cell of the battery is tested forspecific gravity and the dial is turned to the proper position. In

other words, in either case the dial 8 is turned into proper positionfor either theampere hours or for the gravity noted, so

that the roller will rest over the figure in the dial which correspondswith the ampere hours indicated in the meter or the gravity indicated bythe pilot cell. .As has been described above, this first step 6gradually widens from one end to the other. .If, for example, thebattery is shown to be wholly discharged, the drum will be so turnedthat the cursor will rest upon the widest portion of the step 6. If thebattery is considerably less' discharged, it will rest upon a narrowerportion of the step 6,the width of this step, as has been said, beingdetermined by the type of battery in question.

Referring now particularly to the form of devices shown in Figs. 1 to 5,when the current is turned on from the generator throu h the circuits35-36, it will pass through t e metallic switches 4041-4243 and 49 intothe battery, only a very small portion, of

course, passmg through the resistance coil 44. At the same time thedriving mechanism being set into motion, the screw is rotated and thecarriage bearing the lever begins to travel longitudinally of the drumtoward the other end, the roller bearing upon the surface. As soon asthe edge of the step is reached, the end of the arm carrying the rollerwill drop to the next step, 6", causing the other end of the lever torise and bringing the contact plates 23 and 24 into electricalconnection by means of the contact point 30. A portion of the current,therefore, will flow through the wire 38, contact plates 23-24, wire 54,back to circuit wire 36, energizing the coil 54 and opening switch 40,which will thereupon cause the current to pass through the portion 44 oftheresistance 44 and thence, by means of wire 45, through the otherswitches 414243-49 to the battery, thus interposing an aliquot portion44 of the resistance 44 into the circuit, and causing a less amount ofcurrent to flow through the battery as long as the roller it falls upon6, causing plates 24 and 25 to be thrown in contact, thus energizing, inthe same way as above described, the coil 51. opening switch 41, andthrowng an aliquot portion of the resistance 44 also into the circuit,thus further diminishing the flow of the current into the battery. Thus,without going further into detail, as the roller goes from step to stepswitches 42 and 43 are opened, finally throwingin for the last step ofthe charging the entire resistance 44. When the roller drops from thestep 6 to the step 6", the circuit is completed through the wire 38,charging plates 2324-25 262728 and wire 64, energizin coil 62, openingswitch 49, and cutting o the battery from the generator.

From what has been said above, the operation of my devices when operatedwith the form shown in Fig. 6 will be clear, but it may be well torecapitulate it. The drum being rotated so as to be set at the desiredswitch 49 closed, whereby the entire current from the main line flowsthrough the resistances 44-44"44"-44 into the-battery. As the rollerprogresses along the drum longitudinally thereof, it falls down upon thesecond step. The contact between plates 23 and 24 is thereupon closedand coil 109 energized, closing switch 100, thus causing the current toflow around resistance 44, throu h wire 35 and switch 100, increasing,for t e time being, the charging rates. When the roller falls upon thenext step, contacts 24 and 25 are closed, the coil 110 is energized, theswitch 101 is closed and the resistance 44 is cut out, the currentflowing through switch 101 to wire106. Thus, as the movement progresses,coils 11l112 are progressively energized, opening switches 102103 andcutting out still more resistance. When the roller falls upon the laststep, the coil 62 is energized, as before, opening switch 49 andbreaking the charging circuit to the battery.

I have illustrated in the developed drum shown in diagrammatic Fig. 4,by means of two lines XX and Y Y, different positions of the roller asit travels along the plate. For instance, if the battery should be foundto be considerably over half discharged, the roller will be set,,forexample, so that it will fall on line X-X, and traveling along thatline, will continue at a maximum rate from X to D for a considerableperiod. -If, on the other hand, the battery had been discharged only asmaller shorter times.

the line, say, YY. in which case the initial charge, at the high rate,would be continued during only the interval represented by YE. Thus,owing to the shape of the successive surfaces of the drum, where theinitial charge is continued at a given rate for considerable time, asfor a battery which has been almost entirely discharged, the other stepswill continue for relatively If, however, the initial charge iscontinued for a shorter time, owing to the battery having been lessdischarged before the recharging begins, the other steps will continuefor relatively longer times, as is indicated by the width of the steps.It will thus be seen that the battery takes account not only of the timeelement, varying the charging rate at proper periods, and also of thenature of the battery according to the position of the steps on thedrum, but also, by means of the adjustment of the'drum at difierentpositions preparatory to the charging, it takes account of the initialcondition ofthe battery and modifies the. successive rates in chargingaccording to such position.

It will be understood, of course, that some suitable device is providedby which the switches at the beginning of a charging operation may bemanually closed when it is desired to increase the charging rate oropened when it is desired to decrease the charging rate, according tothe form in which my apparatus is used, but such device may be of anywell-known character and is well understood, and forming no part of mypresent invention, '1 have not illustrated the same in order not toencumber the drawings and description with needless matter. It will beunderstood, of course,

that the several parts are mounted in suitable supports and in suitableframework, which may be of any well-understood or preferred type andwhich form no part of my present invention. I have, therefore, not shownsuch framework and supports in full, as to do so would onlyunnecessarily encumber the drawings and description. It will also beunderstood that my invention is not limited to the forms of switches andcircuit breakers shown, as any suitable form of electrically-operatedswitch maybe used and the resistances may also be otherwise arrangedwithout departing from the spirit of my invention.

I have shown the stepped device on which.

dinal movement is concerned, and have given the lonitudinal movement tothe roller. That also is the most convenient, mechanical form, and hencethe preferable form, of my device. It is obvious, however, that otherforms might be used instead of a drum and that the drum and roller mightbe otherwise relatively moved with reference to each other and still bewithin the spirit of my invention. I, therefore, do not confine myselfto a drum except as specifically claimed 01' to have the roller itselfmove along a stationary drum except as specifically claimed, as it isobvious that some other form of a stepped device or platen could be usedand some other way of giving the stepped device and the platen arelative movement longitudinally of the stepped device.

I have described my invention as a device for regulating the chargingrate of storage batteries, and that is, of course, its primary purposeand object. It will be obvious, however, that it could be used for otherspecific purposes than for the one named, where it is desired to changethe rate of flow of an electric current, and it can also be used forstill other objects and purposes. Indeed it may be used in various formsfor various purposes in which there is need of an apparatus fordetermining the performance of variable functions related to ordepending tion, an electrical resistance, a platen having a physicalcontour varying in elevation longitudinally thereof, a bearing deviceadapted to bear upon said platen, mechanism for causing said bearingdevice to traverse the varying contour of said platen, and circuitmaking-and-breaking devices operated by the movement of said bearingdevice relative to the varying contour of said platen to vary theresistance in the circuit.

2. In an apparatus for varying the resistance in an electric circuit, incombina tion, an electrical resistance, a platen having a physicalcontour varying in elevation longitudinally thereof, a bearing deviceadapted to bear upon said platen, mechanism for causing said bearingdevice to traverse the varying contour of said platen, mechanismoperated by the movement of said bearing device relative to the varyingcontour of said platen to vary the resistance in the circuit, and meansfor varying the intervals between successive variation of resistance.

3. An apparatus for varying the resistance in an electrical circuit,comprising a resistance, a member adapted to be actuated to include moreor less resistance in the circuit during different intervals, and acontroller controlling the actuation of said member, said controller andmember being relatively adjustable to vary the length of certain of suchintervals.

4. In combination, an electric circuit, a variable resistance, a steppeddrum, a hearing device adapted to be yieldingly held in contact with thesurface of said drum, means for giving to said bearing device a movementlongitudinal of said drum, and means operated by said bearing device asit moves longitudinally of said drum to progressively vary saidresistance.

5. In combination, an electric circuit, a resistance,,a drum adapted tobe rotated to set the same in any desired position and provided with aseries of steps of progressively diminishing. diameter, a lever adaptedto yieldingly bear at one end upon the surface of said drum, means forcausing said lever to move longitudinally of said drum, and meansoperated by the passing of said lever from step to step on said drum toprogressively vary said resistance.

6. In combination, a main electric circuit,

a resistance, a drum provided with a'plurality of steps of progressivelydiminishing diameter from one end of said drum to the other, a leveradapted to yieldingly hear at one end on said drum, means for movingsaid lever longitudinally of said drum, a plurality of contact platescorresponding in number to the steps on said drum and adapted to besuccessively moved into .contact with one another by one end of saidlever as the other end passes from step to step on said drum, electricalcircuits between each of said contact plates and said main circuit, andmeans operated by said circuits from said contact plates as they aresuccessively brought into contact with one another to. progressivelyvary the amount of said resistance as said lever passes from step tostep on said drum.

-electric circuit, and, circuit making-and- 7. In combination, a platen,a bearing deviceadapted to travel along said platen,

means for giving said bearing device and said platen a longitudinalmovement relative to each other, the surface of said platen beingadapted by the relative movement of said bearing device therewith tomove said bearing device into dinerent positions, an

' breaking devices operated by said bearing device inits movement intodifferent, positions to vary the resistance in said circuit.

8. In combinatioma drum adapted to be set in any desired position andhaving a surface adapted to vary the position of a bearing devicetraveling alon the same, a bearng device yieldingly he d-in contact withthe surface of said drum, means" for giving said drum and said bearingdevice a relative movement longitudinally of said drum, an electriccircuit, a resistance, and means operated by said bearing device in itsmovement into different positions to vary the said resistance in saidcircuit.

9. In combination, an electric circuit, a variable resistance, a memberhaving a stepped surface, the margins of certain of said steps beinginclined, a bearing device adapted to traverse said steps in contactwith the surface of said member, means for moving said bearing deviceover said stepped surface, means for varying the line of travel of saidbearing member over said steped surface, and means operated by saidbearing device as it moves over said stepped surface to vary the amountof resistance in the circuit. I

10. In combination, an electric circuit, a variable resistance, arotatably mounted stepped drum, the margins of certain of the steps ofthe drum being inclined, a bearing device adapted to traverse the stepsof said drum, means for moving said bearing device over the surface ofthe drum, and means operated by the movement of said bearing device fromone step to another to vary the resistance in the circuit.

11. The combination of a platen having a physical contour varying inelevation longitudinally thereof, a bearing device adapted to bear uponsaid platen, mechanism for causing said bearing device to traverse thevarying contour of said platen, and circuit making-and-breakin devicesactuated by the movement of said bearing device from in the circuitduring different intervals, a

controller controlling the actuation of said member, and means wherebythe length of certain of said intervals may be varied.

13. 'An apparatus for varying the resistance in an electric circuit,comprisin a resistance, a traveling member adapte to be actuated toinclude more or less resistance in. the circuit during differentintervals, a rotatably mounted controller adapted to swing about an axisparallel with the line of movement of said member;- and having a iioseries of steps arranged longitudinally of its axis, and means operatedby the movement of said member into engagement with the' different stepsfor varying the amount of resistance in the circuit.

14. An -apparatus for varying the resistance in an electric circuit, comrisin sistance, a traveling member adapter? to be noi actuated toinclude more or less resistance in the circuit during differentintervals, a rotatably mounted controller adapted to swing about an axisparallel with the line of movement of said member and having a series ofsteps arranged longitudinally of its axis, certain of said steps havingmargins inclined with reference to the line of movement-of said member,and means operated by the movement of said memberinto engagement withthe different steps for. varying the amount of resistance in thecircuit.

15. The combination of a plurality of contact devices normallydisconnected from each other and adapted to be moved successively intoelectrical contact with one another, a bearing member adapted to beactuated to move one or more of such contact devices successively intocontact with the adjacent contact device, a controller for controllingthe actuation of said bearing member, comprising a platen having aphysical contour varying in elevation longitudinally thereof, saidbearing member being adapted to bear upon said platen, and mechanism.for causing said bearing member to traverse the varying contour of saidplaten to vary thet number of said contact devices in circui 16. Anapparatus for varying the resistance of an electrical circuit,comprising a resistance, a member adapted to be actuated to include moreor less of such resistance in circuit during different intervals, and arotatably-mounted controller controlling the actuation of said member,said member being movable longitudinally of said controller to vary theresistance in the circuit during different intervals, being adjustabletransversely of the line of movement of said member to vary the lengthof certain of such intervals.

17. The combination of a plurality of contact devices normallydisconnected from each other and adapted to be moved successively intoelectrical contact with one another, a bearing member adapted to beactuated to move one or more of such contact devices successively intocontact with the adjacent contact device, a controller for controllingthe actuation of said bearing member, comprising a platen having aphysical contour varying in elevation longitudinally thereof, saidbearing member being adapted to bear upon said platen, and mechanism forcausing said bearing member to traverse the varying contour of saidplaten to vary the number of said contact devices in circuit, saidcontroller and bearing member being relatively adjustable to vary theactuation of said contact devices by said bearing member.

ALEXANDER H. Foss, HARRY L. STANTON.

and said controller

